It is well known that, in general, a single-lens reflex camera has a movable mirror behind the photographing lens, and switching between the photographing state and the viewing state is accomplished by moving the mirror. The movement of the mirror end it greatly limited by the photographing lens and the film or the shutter is provided behind the mirror so that the size of the mirror is limited to a certain value. This invention relates to a so-called retracting and raising type mirror drive device for a camera in which, in spite of the above-described conditions, the size of the mirror is increased in order to transmit as much light as possible, and in which device at the time of photographing the mirror is not only swung but moved, or retracted, away from the photographing lens. Mirror drive devices of this type are intricate in construction and usually include a number of sliding components which require a relatively great force to operate.